This invention pertains to the field of grass and lawn edging and borders, and similar structures for controlling the growth of ground cover plants at lawn edges or around decorative plants such as bushes or trees.
U.S. Pat. No. 4,969,289 to Trifiletti discloses an edging material having a skirt extending out from a rectangular upright section. FIG. 2 shows in cross section the construction of this item. The article requires stakes to secure it. FIG. 6 shows a circular form of the article.
U.S. Pat. No. 3,724,128 to Tabone shows an extruded edging, of plastic, for use as a planter as around a tree. The patent shows a vertical, soil dividing section.
U.S. Pat. No. 4,858,378 to Helmy shows a modular planter which includes a cover extending to and surrounding the trunk of a plant. A circular version is shown.
U.S. Pat. No. 4,934,093 to Yanna shows a circular collar having both an inner and an outer border with a raised edge. This patent discloses that such edging will limit plant growth beneath the edging, and is thus useful for forming borders.
U.S. Pat. No. 3,777,421 to Bomba et al describes a two part lawn border; a flat base member is laid to form the border, and a cap member is snapped to the base to complete the border. This patent describes the use of an outwardly extending edge for supporting a lawn mower wheel so as to provide clean lawn edging. A two pan structure is stated to be necessary to avoid ground movement with frost.
U.S. Pat. No. 4,976,063 to Young discloses a lawn edging system for bordering a plant composed of interlocked curved and straight segments.
U.S. Pat. No. 2,654,180 to Redfield claims a lawn edger formed of a border material embedded in the ground at a lawn edge.
U.S. Pat. No. 2,782,561 to Smith discloses a tree surrounding ring.